In electrical machines with permanent excitation and permanent magnets arranged at the air gap, the retaining force of the permanent magnets on the rotor body is of decisive importance for the operational reliability of the machine. Previous fixing solutions are based on mechanical connections or adhesive connections. In doing so, the usually flat permanent magnets or magnet systems (comprising a base plate and permanent magnets fixed thereto) are screwed, clamped or glued to the rotor body, as the magnetic retaining forces alone are not sufficient to retain the permanent magnets reliably on the rotor body under all operating conditions.
Fixing solutions which have been disclosed in the prior art are shown in FIG. 1. In the top diagram in FIG. 1, the permanent magnets 3 are attached to the rotor body 4 by means of shaped plates 10 and cartridge-fired pins/rivets 13. In the middle diagram in FIG. 1, the permanent magnets 3 are pushed into trapezoidal slots made in the rotor body 4 and in this way fixed to the rotor body 4. At the same time, the permanent magnets are additionally fixed by means of cartridge-fired pins/rivets 13 and the element 21.
In the bottom diagram in FIG. 1, the permanent magnets 3 are embedded in a sleeve 12, wherein the sleeve 12 is attached to the rotor body 4 by means of a dovetail joint. Additional pressure is exerted on the dovetail joint by means of a clamp 20 in order to additionally increase the fixing of the permanent magnets.